What is the size of the watershed draining into Lake Koshkonong ?
The watershed that drains into the Rock River and ultimately Lake Koshkonong is about 1,900 square miles and is called the Upper Rock River Watershed. The Upper Rock River Watershed downstream boundary is at Fort Atkinson . A smaller subwatershed that includes the lands that drain to the Rock River between Fort Atkinson and the Indianford Dam contain another 400 square miles for a total of approximately 2,300 square miles.
